Pusher



s. B. MARTIN l 2.366,923

PYUsHER Filed oct. 7, 1942 2 sheets-sheet 1 ,4 fr@ E' A/fys Patented Jan. o. 1945 UNITED Y Stoddard'.

Application October'l, 1942,` Serial No. 461,138` I `16 claims.

ieedngersor` pushers of the typeemployed in `automatic screw machines.

ing a collet at its forward end which is arranged `to becompressed radially to grip and rotate ay bar of stock fed axially through the tube. n At the end ofneach cycle of operation the projecting @end of stock is cut off `from thebar, whereupon the collet opens anda new length of stock is fed forwardly andthe collet is again closed to gripthe stock `and repeat the `cycle of operation. The stock is ordinarily fed'forward by a pusher car- `ried by a reciprocating pusher tube arranged be- 1 tween and coaxial with the collet tubeand the bar of stock." 1

VIn the `conventional machine the pusher is simply a spring bushing exertinga constant grip on the :bar `of stock which is moved forwardly after the colletopens until the forward end of the bar strikes astock gauge.

`vent rebounding when the bar strokes the gauge,

`there is danger of scratching or scoring the stock whenthe pusher` is retracted.` Another disadvantage of such an arrangement is that the pusher exerts a constant grip on the bar stock during .both the feeding and return strokes so that the `gripping surfacesl of the pusher are rapidly worn out by the friction of the return strokes.`

The principal objects of the presentinvention are to combinein a pusher for machines of this type means to effect a` one way gripping action, removable pads or bushings to accommodate all different sizes of stock up to and includingthe maximum capacity of the machine, and means ,for preventing the-wedging or tight gripping action of the pusher whenit is desired to'lwitho `Each spindle of `an automatic screw machine ordinarily surrounds a rotating collet tube hav- The collet then i t `grips the bar` and the pusher is retracted. One `of the disadvantages of this arrangementis that vwhen the .pusher is given a sufficiently tightgrip .on the bar to insure Aaccurate feeding and predraw the bar of stock; to arrange the pusher soy that the bushings may be removed or replaced without removing the pusher tube from the `machine; to maintain the wedging and wedge re-` lease `mechanism within the thickness of the Walls of the pusher shell; to eliminate loose or l readily separable parts other than the removable .bushing or pad units; to Imaintain `the wedging element of the pusher shell circumferentially` continuous so as to insure apositive `grip on the o "stock without dangerlof slipping;` to `permanently mount on the bushing abutment elements which cooperate. with the shell; to maintain "the abut- `bushing from the shell;`

tions or pads of the bushing; i

(o1. zei-e2) This invention relates to improvements instock ments on `the shell and `bushing -in cooperative relation regardless of whether or `not1stoclcis `gripped within the pusher; `and to improve and simplify the construction and the manner of assembling and disassembling the removable bushings` in the shell. Other objects and advantages o will appear from kthe following detailed description of the embodimentsof theinvention.

lIn( the accompanying drawings: l

Fig. l is a. side elevation of a pusher constructed in accordance with this invention; y Fig. 2 is across section through the stock on the line 2-2 of Fig. 1 showing the front end of the pusher in elevation;` o

`Fig. 3l is a. longitudinalsection through the `pusher taken on the line 3--3 of Fig. l;

, Fig. 4 is a cross section taken on theline 4--4` ofFigla .no o

. o Fig. 5 is a `longitudinal section through the pusher showing themannerof` removing the Fig. 6 is a perspective view-of one i Fig. 7 is a perspective Viewof a Fig. 8 is a side pusher;

` Fig. 9 is a cross section throughfthe stock onv thel-line 9-9 of Fig. 8` showing the end" of the pusher in elevation;

Fig.` 10 is'a cross section Ill--IU of.Fig.18; and l l o .Fig.V `11 is a partial longitudinal section taken on the linell-II of Fig. 10. 1 1

i Referring to the drawings," the embodiment of the invention illustrated in Figs. 1 to 7,inclusive, includes a shell I5 which issecured in any suitable manner to the forward end cfa pusher tube I6 disposed within the collettube` (not shown) of an automatic screw machines` If desired, the

taken l on :the line 'forward end ofv the shell may be counterbored l "inwardly from its frontgface, *as indicated at l1,

to provide a seat for the bushing. i L-shaped {cutouts I8 are `cut through the wallof the shell. One such cut-.out isprovided for each section of the bushing, there being four cut-outs I8"equ`al1y spaced about the shell in the embodiment illustrated.-`

The bushing is rnadeupof four segments or l pads 2U separated from each `otherbyslotsZI.

t a cylindrical outer surface which ilts` freely l The rearward portion of the Ibushingfdesigned toflwt within the counterbore vl'l of 'the..shell,has

in the shell when the bushing` isexpandedvltqt `of the secl U forni of tool .-for removing the bushing from the shell; l elevation of a modified fformof.`

.lretracting `stroke of the pushertube.

rout also has a Ilaterally disposed notch 30spaced Iends slightly.

stocki of the maximum size'intended to be handled by the-particular bushing.

shell and the bushing isthen forced rearwardly until the lugs snap into the cut-outs I8. To relmove the bushing the front ends of the slots 2| are spread, forcing the spring 25 open and fulcruming the segments about the front edge 23 of the shell until the lugs 21 are forced inwardly far enough to clear the wall of the shell, after which the bushing can be withdrawn forwardly.

the bottom of the groove 24 or theunder surface of the spring .25 is"` tapered so thatftheinitial engagement of the spring upon the bushing iis at the forward edge of the spring, leaving a'slight space 26A between the groove and the rear edge of the spring when the bushing is expanded andv is gripping stock as illustrated in Fig. 3. If de` sired, both the groove and the spring may be tapered to form the space` 26. y

Each of the segments or pads 26 For conveniently effecting such removal I provideja' tool` 32 consisting rof"af-friiigf-3 3 Icarrying four wedge lugs 34 and'v 4mounted erta rod 35 terminating in a handle 36. The rod 35 is pref- `erably made of sufcient length tolpermit thet tool to be inserted through the collet of the machine to engage the bushing without disturbing y `the assembly of the pusher tube Within the collet 'is provided i with a stud 21 projecting from the outer surface y thereof through a `distance about equal to the thickness'v of the wall'of the shell I5andv adapted'to t yinone of the'cuteouts I8. r-Preferably the studs ,21 are square in 'outline as shown. The

`studs are permanently secured to the padsv in any' convenient manner as by threaded shanks screwed into tappedopenings in the pads. Preferably the studs' are screwed into placev with two of their edges parallel' with the axis of the bushing and are then'welded. i Manifestly the studs may be fixed ,te the pads in any other desired manner, as by simply welding tothe 'outer' surfaces.` l f The slots 2'I separating the pads from each other are of greater width than needed to provide the desired 'expansion of [the bushing to grip the stock. At a point spaced rearwardly from the forward edge of the spring 24 and in advance of the'studs 2,1the adjacentedges `of the 'padsfare 'provided with fulcrum. abutments. In the 'illustrated embodiment' this is accomplished by welding a lug 28 to oneedge of each ofthe pads 2U. Each lug 28 is then 1in position to engagethe straight edge of the adjacent pad but is spaced' a` short distance .therefrom when stock is gripped'within ther bushing, as illustrated Each of the cut-outs I8 formed in the -shell is designed to receive one Iof the `lugs'21 yand is formed with "a greater axial length4 than the axial length of its lug 21 so as to vpermit relative axial movement between the shell and the, bushing. Each cut-out has a rearwardly' facingedge 29 arranged to engagev the forward zedge .of `the lug 21 to pull the bushing over the stockfon the Each cutrearwardly a` short distance from the edge.v 29, leaving a shoulder 3 I Each notch 3U is arranged to `receive a lug 21 to limit. relative aXial move- 2 ofy thel adjacent pads. The tension exerted byf lthe 4front edge of the spring, which yis infront ofthe abutments 28, rocks'th'e frontends of the pads toward each other about the fulcrumabutments 28 untilthe space 26 atl the rear' end of the spring v25 isv closed. This partiallyv closes the;r

front ends ofthefslots 2l and` opens the -rear Toassemble the bushing in theshe'll the rear vends ofthe segments 20v are collapsed togetherA Until 4the"'1lr1'gs*`2'|= can brillerI tlier-lflt 'end 0f the;

tube of the machine. The wedge lugs 34 are vspaced so that one enters each of the slots 2|, ,andl are designed to spread the slots the necessary amount by driving or pushing the tool inwardly, asv illustrated in Fig. 5 l l "In operation the stock Sis normally gripped by the bushing with the force determined` `-by the strength 'of the spring 25. When theY pusher tube advances to feed stock forwardly the y-forjward edge 423 of the shell' I5 engages the tapered'surface '22 on the bushing, tightlysqueezing the bushing upon the stock and feeding'the same -withoutslippi'ngA A positive gripnis lassured by making the front edge of tlfiefsh'ellI4 circumfer` entially continuous;asfillustrated. On the re-` tracting stroke the shell slides rearwardly until the edges 29 ofthe cut-outs I8 engage'the studs 21 and pull the bushing rearwardly-over the stock against the relatively light grip provided by the spring 25.

In certain machines the pusher tube is :keyed to the spindle so that thepusher` tube and stock rotate together while the vcollet `is closed, ITar-1d the tube drives the bushing when the collet is opened.` In. such machines, when'ltheil'rotation of the spindle is counterclockwise as viewed from the front end, thestuds 21 normally remain: on the clockwise sidel of the cut-outs I8 andthe `notches 6I)Y are formed 'onf the counterclockwise .and thetaperedsurface 22 ofr the: bushingzii .Preferably the `notches 30 areuspaced slightly ftolthe rear of the edges' 29 of the fout-'outs leaving the shoulders 3|.V Thus lduringtlsre retracting stroke the/studs 2.1 are ,seatedl against the edges 29 and are: prevented from` :enteringthe notches 30 by the shoulders 3|.. `'In'withdrawing the bar it is only necessary .to--slipgt axially to bring the studls 21. into `alignment withthe In theform ofthe invention i.illustratedv an Figs. 8 to loinclusive av'slightlydiierentnfbnn `.provided with a taperedrsurfacevlf2^2 forfwedgiing vengagement'withthe forward 'edge'. 51.213.; of vthe shell I.:I5.L In advance of theitaperedsurface^=li22 n the bushing is formed withziartapered groove 1214,

sition with stock gripped in the bushingengages the groove at i its forward edge and is `spaced from thegroove at its rearward edge by "a space |26. i -Each of `the `segments `|2|1 is provided at its rear end with an integral lug |21 adapted to i `work in one of the cut-loutsll in the shell in `the same manner as in the embodiment previously described.` Fulcrum abutments |28 are provided between the pads by cutting `the slots l|2|` forwardly into the bushing from the rear `end `thereof to a point spaced rearwardly from `the forward edge of the spring groove |24. .The

slots `are then completed rbyfcutting from the forward face of the bushing with atapered milling cutter, leaving an abutment |28 projecting from each edge of each of the segments.

, In this form ofthe invention the, bushing is arranged to be removed in a slightly different manner. Each of thelugs |21 is formed with a radial edge |40 and a beveled edge |4I. Whenit is desired to remove the bushing from the, shell the bushing is turned to bring the' lugs |21 into Athe notches |30, and is then forcibly turned` the shell'in the same manner as in the embodi` ment previously described The lugs |21 may alsobe provided with beveled edges |42 cooperating with complementally Ibeveled rearwardly facing edges |29 of the cut- Quts H8.` These edges engage to slide the bush-` ing overx` the stock on the retracting stroke lof the pusher and are lbeveled, as illustrated, sol as to exert a `component, of the retracting force `radially outward` on each segment l |20, `thus "avoiding any possibility of the lugs |216 escaping from the cut-outs H8. 4

Although the embodiments'of the invention `have been described in considerable detail,`it

will be understood thatvarious rearrangements and modifications of detail may be resorted to `without departing from thescope of the invention as herein claimed.

` I claim:

1. A pusher` comprisinga shell, a bushing adapted to grip stock to be fed disposed within said shell, a w'edging surface on said bushing f cooperating with the forward edge oflsaid shell t'o increase the grip of said bushing on the stock when said shell moves forwardly with `respect tosaid bushing,"said shell being`fo1medwith l an opening through `the wall thereofya stud secured to said bushing and projecting intdsaid said shell to move said bushing rearwardly when` `in'said shell yto move said"bushing"rearw`ardly when said shell moves rearwardly. 3.\In a pusher, a shell, a bushing comprising a plurality of "segmental pads and a spring'sur'- rounding said pads, said bushing having one end disposed within said shell and `adapted to grip stock to be fed, cooperative wedging means on said shell and` bushing arranged to increase the grip of said bushing on `the stock when said shell moves forwardly with respect to said bushing, said shell being formed with a plurality `of open-` ings through the wall thereof, a stud secured to each of said segmental pads and projecting into an opening in said shell, each of said studs being arranged to engage one edge of its opening in said shell moves rearwardly, the other end of said bushing projecting rfrom said shell and being arranged to be spread to free said studs from their openings and permit the Yremoval of vsaidV bushing from said shell.l l

l 4.\In a pusher,` a cylindrical shell having its forward edge circumferentially continuous, a bushing comprising a plurality of segmental pads and a spring surrounding said pads, said bushing having one end disposed within said shell and adapted to grip stock'to be fed, a wedging surface on said bushing arranged to engage the for-` ward edge of said shell to increase the` gripl of saidbushing `on the stock when said shell. `moves forwardly with respect to said bushing, said shell being formed with a plurality of openings through the wall thereof, a stud secured to each of said lseg-mental pads and projecting into an opening in said shell,` each of said studs being ar ranged to engage one edge of itsopening in said` shell to move said 'bushing rearwardlywhensaid shell moves rearwardly,` the other endof said bushing projecting from the forward edge `of openinginsaid shell, said stud being arranged to engage one edge of the openingin said `shell tomove said 'bushing rearwardly when said shell moves rearwardly.

2. A pusher comprising a cylindrical shell having its forward edge circumferentially continuous, a bushing adapted togrip stock to be "fed disposedwthin said shell, a wedging surmoves :forwardlyfwithrespect to said bushing, said shell being formedwith an opening `through manently carried by `saidbushing and projecting intqsaid opening in said shell, ,r saidstud lirene:ar 1tar 1eefl149engage@reggae Qfleepteile igpadjafryng a sind leaiedreafwardlr fad bushing partially disposed within said' shell hav-` said shell and being arranged to be spread tofree said studs from their openings and permit the removal of said bushing from said shell.

5. A pusher comprising a cylindrical shell, a bushing disposed within said shell comprising a plurality of segmental pads, a spring surrounding said pads and holding the same assembled in `each of said pads carrying a stud located on said other side of said abutments and arranged to fait in one of said openings, 6. A` pusher comprising `a cylindrical shell, a

ing `its forward end projecting `from said shell, said bushing comprising a plurality of segmental pads, a spring surrounding said pads outside of said shell and holding said pads assembled, each `of said pads havingan abutment on one edge adapted to engage the edge of an adjacent pad, said spring being arranged to exert a radial com- `the wall thereof,` a radially projecting stud perpressive force on .said pads forward of said abutments so as to urge theforward ends of said pads toward each other and therear ends of sadpads i away from each other, said shell being formed with a plurality of openings and each of said abutmerits and arranged: to t .in one of said openings.

"1.' A'pusher comprising a` cylindrical shell, a

bushing disposed within said shell and arranged btogrip stock to be fed comprising a plurality of segmental pads, cooperating wedging surfaces on saidr shell and bushing arranged to increase the grip of said bushing on the stock when` said shell.moves forwardly withrespect to said bushing', a spring surrounding said pads and holding I0 i the same assembled in generally cylindrical form, `each of. said pads having an abutment' on one edge adapted to enga-gev the edge of an adjacent pad, said spring being arranged to exert a radial compressive force on said pads on one side of said abutments so as to yurge the ends of said pads toward each other on said one* side of saidlabutments and to urge Vthe ends of said pads away from each other on the other 'side of said abutments,. said shell being formed with a plurality of openings and each of said pads carryvinga stud located on said other side of said abutments and arranged to t in one of said openings. 8. A pusher comprising a cylindricall shell, a

bushing having its rear end disposedl within said shell and its Yfront end projecting therefrom, said bushing comprising a plurality of segmental vpads and a spring surrounding said pads to resilientlygrip stock to be fed, cooperating wedging surfaces on said shell and bushing to in `30 crease the grip of said bushing on the stock when said shell moves forwardly with respect to said bushing, each of said pads having an abutment on one edge adapted to engage the edge of an adjacent pad, said spring being arranged to eX- `ert a radial compressive force on said pads in front" of said abutrnentsv so as to urge the front ends of said pads toward each otherand to urge the rear ends of said pads away from each other,

saidy shell being formed with a plurality of open- 40 ingsand each of said pads carrying a stud located in rear of said abutments and arranged to lit in one of said openings. i

9. vA pusher comprising a cylindricalv shell, La

bushing having its rear end disposed within saidv vL1-5 shell and its front end projecting therefrom,

said bushing comprising a plurality of segmental pads and a spring surrounding said pads outside of said shell to resiliently grip stock to be fed,

a wedging surface on said bushing arranged to"550 engage the front end of said shell to increase the grip of said bushing on the stock, each of of said pads away from each other, said shell being formed with aplurality of openings andi c() each of said padsv having a stud permanently secured thereto in rear of said abutments and .arranged to t in one of said openings, the front ends of said pads being arranged to be spread .to free said studs 'from the openings in said 65 shell to permit the removal of said'bushing.

10. A pusher comprising a shell, a bushing adapted to grip stock to be fed disposed within said shell, cooperating wedging means on said shell and bushing arranged to increase the grip of said bushing on the stock when said shell moves forwardlyl with respect 'to said bushing, said shell being formed with an opening through the wall thereof', a stud, permanently` carried by vf4 'assegnare said; shell said stud; having al beveled edge, ar-

-rangedtof yengage a. correspondingly beveled edge inthe opening in said shellto move said Ibusi-1f- 'ing rearwardly when said shell moves rearwardly,

and said beveled edges being arranged. to exert a, component of thegretracting force-of said'shell radially outward on said stud.

11. aypusher, a shell, a bushing, comprising smontare, fed, said; Shen being forme-d with. a

to. engage a, correspondingly beveled edge.- of4 its opening in. said` shell, to .move said'. bushing rear'- 'wardly when said shell `moves rearwardly,A said beveled.` edges being varranged to applyr a component. of the force of said shell to spread the inner ends of said pads. radially outward.`

12. A pusher comprising a. cylindrical shell, a bushing having its rear end disposed within said s hell and` its front end projecting therefrom, said bushing comprising a plurality 0f segmental pads and a spring surrounding said pads to resiliently grip stock to be fed,-cooperating Wedging surfaces on said shell and bushing to increase the grip vof said bushing on the stock when said. shell moves forwardly with respect to said bushing, each of said pads having an abutment on one .edge adapted to engage. the edge of an adjacent 4 pad said spring being arranged to exert a. radial compressive force on. said pads` .in front of said abutments so as to urge, the iront ends of said pads toward each otherand tourge the` rear ends of said pads away from each other, said shell being` formed with a. plurality of openings and eachof` said padscarrying a stud located. in. rear of said abutments and arranged to t in one of said openings, the forward edge of each of said studs being undercut. and adapted to engage` an edge of its opening so. that rearward lmovement of said shell holds'therear ends of said padsk against inward movement.'

1 3. A pusher `comprising a shell, a bushing adapted to grip stock to be fed disposedv within said shell, cooperating wedging means on said' shell and bushing arranged to increase the grip Aof said bushing on the stock when said shell the wall thereof', a stud permanently carried'by said bushing rearwardly'of said wedging means and projectingl into said opening vin said shell, saidt stud being Aarranged to engage one edge of the opening. in said shell to move said bushing rearwardly when said'Vv shell moves rearwardly.

14. Apushe, comprising a shell, a bushing adapted to -grip stockl to be fed disposed lwithin said shell, al wedging surface on' said bushing cooperating with the forward edge of said shell to increase the grip of said bushing on the stock when saidr shell moves forwardly withfrespe'ct to said. bushing, said. shell being formed with an opening through the wall thereof, a stud permanently carried by said bushing and projecting said bushing and projecting into said opening' 75 Ytion of Asaid bushing carryingsai'd: Studi beingconstructed to resiliently urge said stud radially outward into said opening.

15. A pusher comprising a cylindrical shell hav- `ing its forward edge circumferentially continul ous, a bushing adapted to grip stock to be fed disposedwithin said shell, a wedging surface on said 'bushing arranged to` engage the` forward edge of said shell to increase the grip of Isaid bushing on thestock when said shell moves forwardly with respect to said bushing,` said shell being formed with an opening through the wall thereof, a radially projecting stud permanently carriedby said bushing and projecting into said opening in said shell, said stud being arranged to engage one edge of the opening in said shell to move said bushing rearwardly when said shell moves rearwardly, said bushing being constructed to resiliently contract upon the stock to be fed adjacent its forward end and the portion of said bushing carrying said stud being constructed `to resiliently urge said stud radially outward into said opening.

16. A pusher comprising a shell, a bushing adapted to grip stock to be fed disposed within said she11,a wedging surface `on said bushing cooperating with the forward edge of said shell to increase the grip Aof said bushing on thestock when said shell moves `forwardly with respect to said bushing, said shell being formed with an opening through the wall thereof, a stud integral with a portion of said bushing and disposed rearwardly of said wedging surface and projecting into said opening, said stud being arranged to engage one edge of the opening `in said shell to move said bushing rearwardly when said shell moves rearwardly, said bushing being constructed to resiliently contract upon the stock tobe fed adjacent its forward end and constructed to urge said stud resiliently outward into said opening. l

STODDARD B. MARTIN. 

